Add the following codes in your theme’s functions.php file.

add_action( 'wp_head', 'remove_tracking_form_results_page' );
function remove_tracking_form_results_page(){
	global $wpcargo_track_form;
	if( isset( $_REQUEST['wpcargo_tracking_number'] ) ){
		remove_action('wpcargo_track_form', array( $wpcargo_track_form, 'wpcargo_trackform_template' ), 10, 1 );
	}
}